Load hoisting and lowering skips



Aug. 25, 1959 T. MARTINS LOAD HOISTING AND LOWERING SKIPS 5 Sheets-Sheet 1 Filed Feb. 7, 1956 INvEN QR Tfivmas War 1/073 Aug. 25, 1959 r. MARTINS LOAD HOISTING AND LOWERING SKIPS 5 Sheets-Sheet 2 Filed 7. 1956 V 7 A, g 1

TOR N 551 Aug. 25, 1959 T. MARTINS 2,901,281

LOAD HOISTING AND LOWERING SKIPS Filed Feb. '7, 1956 5 Sheets-Sheet 3 INVENTOR ATTQQNEYS T. MARTINS LOAD HOISTING AND LOWERING SKIPS Aug. 25, 1959 5 Sheets-Sheet 4 Filed Feb. 7, 1956 INVENTOE T. MARTINS LOAD HOISTING AND LOWERING SKIPS Aug. 25, 1959 5 Sheets-Sheet 5 Filed Feb. 7, 1955 ATTORNEYJ United States Patent LOAD HOISTINGAND LOWERING SKIPS Application February 7, 1956, Serial No. 564,069

Claims priority, application Great Britain February. 9,1955

3 Claims. (Cl. 294-459) This invention relates to load hoisting and lowering skips and has particular although not exclusive reference to skips having discharge doors of the guillotine type.

With such skips it is found that considerable force is required to open the door particularly when the skip contains certain kinds of. materials such. as material containing a high proportion of dust and moisture. Such material tends to. press heavily against the door, sometimes wedging the latter into its closed position.

It is an object of the present invention to provide an improved form of skip in which the disadvantages just referred to are substantially avoided.

According to the present invention a load hoisting and lowering skip having a discharge opening is provided with an internal door or flap arranged so, as to retain, when closed, at least the bulk of material loaded into the skip out of contact with an external guillotine-type door for controlling the discharge of material through the opening, means being provided for operating the internal door or flap, at least the initial opening movement of which is in a direction away from material in the skip.

Preferably mechanism for opening the flap or door comprises a linkage which is connected to a guillotinetype door of the skip where such a door exists so that when the latter door is opened the door or flap opens also. Alternatively where there is no guillotine-type door the linkage may be connected to a carriage which moves along an outside wall of the skip. The linkage is preferable self-locking when the guillotine-type door and the internal door are both closed, that is to say, movement of the internal door is prevented unless the guillotinetype door is also opened.

As examples of the invention, several embodiments thereof will now be described by way of example with reference to the accompanying drawings of which:

Fig. 1 is a vertical cross section through the lower part of a first embodiment;

Fig. 2 is a section on the line II-II of Fig. 1;

Fig. 3 is a vertical cross section through the lower part of a second embodiment;

Fig. 4 is a section on the line IV--IV of Fig. 3;

Figs. 5 and 6 are vertical cross sections through the lower part of a third embodiment,

Fig. 7 is a section on the line VII--VII of Fig. 5,

Fig. 8 is a vertical cross section through the lower part of a fourth embodiment, and

Fig. 9 is a cross section on line IX--IX of Fig. 8.

The embodiment shown in Fig. 1 comprises a skip generally indicated by the reference numeral 1, the skip being of well-known form having a sloping lower floor 2 with front and back walls 3 and 4 respectively. The front wall 3 has a discharge aperture, the fiow of material through which is controlled by a guillotine-type door 5. The door 5 is raised and lowered on rollers 6 moving in guides 7 secured to the side walls 8 and 9 of the skip by an operating mechanism of which only a door liftingfinger 10 is shown. The finger 10 engages a cross member 11 on the door and it will be appreciated that 24. upward movement of the finger 10 moves the guillotine: type door 5. upwardly thus permitting the discharge of any material within the skip 1. A suitable form of door opening mechanism. is described in British patent speQific-aa tion No. 731,941 dated September 3, 195,3.

Secured to the inside face of the guillotine-type, door 5 are pairs of brackets 12 between which are pivotally mounted links 13. The Links .13 are, also. pivoted between pairs of brackets 14 secured to the face of an internal subsidiary door or flap 15. As can be seen in Fig. 1 the length of the door 15 exceeds slightly that of the guillotine-type door 5, and with the latter shut the links 13 are practically horizontal whereby movement of the door 15 by pressure of material retained in the skip is prevented. The upper part of the door 1.5 is thus. spaced from the upper part of the guillotine-type door 5. The front wall 2 of the skip 1 also has a screen 16 whose lower end is angled as at 17.

In use, upward movement of the finger 10 lifts the guillotine-type door 5 and thus movement, transmitted through the links 13 causes the door 15 to swing about its lower end and move towards the guillotine-type door 5'. The lower end of door 15 slides down the. surface of door 5 during the motion just described. Continued movement of the finger eventually brings the door 15 into a position in which it lies against the guillotine-type door 5 and both move upwardly together until the door and finger reach the position shown in chain dotted lines which is the fully-open position of the guillotine-type door 5,.

It will be appreciated that material within the skip 1 is held clear of the guillotine-type door 5 by the door 15 and that the initial movement of the latter towards. the former at the commencement of lifting greatly reduces the chance of wedging. Movement of the upper end of the door15 to the. left as seen in Fig. 1 is also helped by the lower end 17 of the screen 16 which is inclined thus producing movement in the required direction.

In the second embodiment shown in Figs. 3 and 4 the. construction of the skip and of the guillotine-type door is identical with that of Fig. l and similar parts have been given the same reference numerals in both figures. The front wall 3 of the skip is formed with a lower portion 18 which extends downwardly and into the interior of the skip 1 and has mounted at its lowermost edge brackets of which one 19 is visible in Fig. 3. Pivotally mounted between the brackets is a door 15 which corresponds with the subsidiary door 15 of Fig. 1. It will be noted, however, that the door 15 of Fig, 3 does not extend completely from the end of the portion 18 to the sloping floor 2 of the skip. From the lower edge of the door 15 links 13 extend towards the guillotine-type door 5. The links 13 are pivotally mounted at one end to the guillotine-type door 5 and at the other end to. the door 15.

In operation, upward movement of the finger 10 lifts the guillotine-type door 5 and the links 13 gradually swing the door 15 about its mounting until the fully-open position shown in chain dotted lines is reached. Again, initial movement of the door 15 is away from material in the skip.

. Reference has been made above to the fact that in the embodiment. of Fig. 3 the door 15 does not extend fully to the sloping floor 2. This allows a limited amount of material to pass the door 15 and comes to rest against the guillotine-type door 5. That limited amount of material partially loads the lowermost part of the skip and serves to balance the latter. This is particularly advantageous in the case of skips which are both deep and narrow where considerable unbalance can occur making loading, unloading and movement of the skip ditlicult.

It will, of course, be appreciated that where unbalance is unlikely to occur the door 15 can be extended so that when closed it contacts the sloping floor 2 of the skip thus preventing completely the passage of material. The general construction of the arrangement in which the door 15 is as just described is the same as that of the embodiment shown in Figs. 3 and 4. The links 13 would be connected at the lowermost edge of the door 15 and would be connected to the guillotine-type door 5 at a point such that when the latter and the door are closed the links are substantially normal ot the plane containing the door 5.

In the embodiment of Figs. 5, 6 and 7 parts similar to those of the two previous embodiments have been given similar reference numerals and it will be seen that the upper part of the subsidiary door 15 is carried between two guides each of which is fixed-to one side wall of the skip. Figure 5 shows that the front wall 3 of the skip is recessed as at 21. The lower part of the door 15 is connected by links 13 to the guillotine-type door 5, one end of each link being pivotally connected to the former and the other end to the latter. The operation of the embodiment of Figs. 5, 6 and 7 is practically the same as that of the previous embodiments. Upward movement of the guillotine-type door 5 first causes the lower end of the door 15 to move away from any material held in the skip and into the position shown in Fig. 6. Thereafter both doors move up together until the fully-open position shown in chain dotted lines in Fig. 5 is reached. In the fully open position the door 15 is accommodated in the recess 21 in the front wall. By recessing the front wall in the manner shown, movement of the door 15 occurs outside the skip as in the embodiment of Fig. 1. The closing movement of the door is the reverse of the opening movement.

By varying the length of the door 15 of the third embodiment just described, and the length of the links 13, the position of material held in the skip can be varied slightly to produce the best balance of the skip. The front wall 3 of the skip shown in Figs. 8 and 9 is formed in a manner similar to that shown in Figs. 5 and 6. The lower part of the recessed portion 21 is outwardly flanged at 22 to form a stop for the internal door 15. The lowermost part of the door 15 is coupled to the guillotine-type door 5 by links 13, as in previous examples. Adjacent the upper part of door 15 are formed ears 28 which support an axle 23 carrying rollers 24. The rollers 24 move in guide tracks 25 secured to the inside surface of the guillotine-type door 5. Co-operating with the stop 22 is a flange 26 fixed along the uppermost edge of the door 14 as viewed in Fig. 8. Movement of rollers 24 in one direction along the guide tracks 25 is limited by a stop 27.

Upward movement of the operating finger 10 lifts the guillotine-type door 5 and this movement is transmitted through the links 13 and causes the lower end of door 15 to move towards the guillotine-type door 5. Gradually the door 15 is drawn towards guillotine-type door 5 as the latter continues its upward movement. At the same time the rollers 24- gradually move along the guide tracks 25 until ultimately the doors reach the fully open position which is shown in chain dotted lines in Fig. 8. t

The initial closing movement of guillotine-type door 5 first brings the flange 26 into contact with the stop 22 of the skip. Further downward movement gradually moves links 13 into a horizontal position so that the door 15 is gradually swung inwardly about rollers 24 which by this time have moved along the guide tracks 25 to their initial positions until ultimately they come against the stop 27. Finally the moving components return to the position shown in full lines in Fig. 8.

In the embodiments described above the links are normal to the surface of the guillotine-type door when the flap is closed and the links are then self-locking so that the subsidiary door will not open unless the guillotine-type 499! i e i Movement of the material from the skip is entirely unimpeded by the subsidiary door since the latter is withdrawn completely from the discharge path of the material. Furthermore, as in the case of Fig. 3 above, the provision of the portion 18 facilitates movement of material in the skip towards the discharge opening.

The constructions just described ensures that material within the skip is kept clear of the guillotine-type door and any wedging or arching of the material against that door is avoided. Also as the subsidiary door opens the weight of material acting on it tends to assist the opening of the guillotine-type door. These factors all combine to reduce the power required to open the guillotine-type door. A further advantage is the effect of the subsidiary door on the centre of gravity of the skip. Existing skips have a preponderance of weight on the discharge side and the point of suspension of the skip is usually off-centre to counter-balance that preponderance of weight. In most cases when the skip is loaded the out-of-balance condition worsens so that the point of suspension is usually a compromise. The type of material with which the skip is loaded also affects its centre of gravity depending upon the density of the material. With a skip embodying the present invention the variations on the centre of gravity are much less and this allows smoother hoisting conditions.

It will be understood that the subsidiary door can be used on skips in which the guillotine-type door has been removed. In that case a sliding carriage is provided in place of the door. The carriage has rollers which move in suitable guides on the skip. The carriage opens the subsidiary door in a manner similar to that of the guillotine-type door described above.

It will be understood that instead of linking the guillotine-type door to the subsidiary door an entirely independent mechanism may be employed for opening the latter. j

I claim:

1. A material container having a discharge opening, a guillotine-type door slidably mounted uponthe container for controlling flow of material through said opening, an internal door having an upper end, hinged members secured to the upper end and to the container whereby said internal door is movable about said hinged members, and an operating linkage secured to said guillotinetype door and to said internal door at a point below said upper end whereby opening and closing movements of said guillotine-type door are transmitted to said internal door for opening and closing the latter, the opening movement of said internal door being in a direction away from material in the container.

2. A material container having a discharge opening and comprising in combination, a guillotine-type door for controlling the flow of material through said opening, rollers supporting the guillotine-type door, an internal door having an upper edge, brackets secured internally to said container, pivot means fixed to said upper edge and mounted in said brackets whereby said internal door is swingable about said pivot means, said internal door retaining, when closed, at least the bulk of material loaded into the container out of contact with the guillotine-type door, guides secured to the container along which the rollers move, and links pivotally connected to the guillotine-type door and to the internal door at a point below the upper edge thereof for transmitting thereto the movement of the guillotine-type door for'opening and closing the internal door, in synchronism with said guillotine-type door, the opening movement of the internal door being in a direction away from material in the container. 1

3. A material containerhaving a front wall, a rear wall and side walls and a discharge opening in said front wall and comprising in combination,.a guillotine-type door for controlling the flow of material through the opening, a lower extension to said front wall extending inwardly of said container, brackets secured to the lower end of said lower extension, an internal door for retaining at least the bulk of material loaded into the container out of contact with said gui1lotinetype door, pivot means on said internal door, said pivot means being mounted in said brackets whereby said internal door is swingable about said pivot means, guides secured to said side walls, rollers supporting said guillotine-type door and movable along said guides, links pivotally secured to said guillotinetype door and to said internal door below said pivot 10 means whereby opening and closing movements of said guillotine-type door are transmitted to said internal door to open and close the latter, said links being normal to said internal door when the latter is closed and the opening movement of the internal door being away from material in the container.

References Cited in the file of this patent FOREIGN PATENTS 490,939 Great Britain Aug. 23, 1938 

